You receive a carbon number from a supplier. 2.4 tonnes CO2 per tonne of product. Looks official. It sits in a PDF, formatted neatly. But who checked it?
In most cases, nobody. The number was estimated internally, plugged into a template, and sent along. It was not reviewed by a third party. It was not cross-referenced against actual production data. It was a best guess, delivered with the confidence of a fact.
The numbers no one is checking
The scale of unverified carbon data in global supply chains is staggering. And the numbers tell the story clearly.
Only 9% of companies comprehensively report all emissions — across Scope 1, 2, and 3 (CO2 AI/BCG 2024). That means 91% are estimating, partially reporting, or not reporting at all.
Even among the companies that do measure, the data is shaky. Companies self-estimate a 25-30% error rate in their own carbon measurements (BCG/CO2 AI 2022). Not someone else’s assessment. Their own.
And the root cause? 70% of companies cite lack of available supplier data as the number one barrier to accurate emissions reporting (MIT survey). The data simply does not exist in most supply chains.
Of the companies that do report, 94% of investors believe corporate sustainability reports contain unsupported claims (PwC 2023). The trust deficit is real. And for Scope 3 specifically, most companies still rely on spend-based estimates or industry averages rather than actual supplier data (BCG/CDP 2024).
Most supply chain emissions are Scope 3 — the hardest to measure and the easiest to estimate. This is where the gap lives.
report all emissions
error rate
#1 barrier
“Most carbon data is not wrong on purpose. It is wrong because no one checked.”
The trust problem is growing
You might expect the situation to be improving as sustainability reporting matures. The opposite appears to be true.
94% of investors believe corporate sustainability reports contain unsupported claims (PwC 2023), up from 87% the year before. The default assumption when someone sees a carbon claim is now skepticism, not trust.
And regulators are responding. The EU is tightening requirements on multiple fronts. CBAM now requires installation-level data, not industry-average estimates. If you cannot provide verified numbers, you get default values based on the worst performers. That is not a rounding error. It is a penalty.
CSRD requires double materiality assessments with verified data. Companies reporting under the directive cannot rely on self-reported estimates for their material impacts. The bar is rising.
Carbon markets are shifting too. The era of buying offsets and calling it progress is fading. The market is moving toward measured, verified reductions — actual data, not promises.
What verification actually looks like
It is worth being specific about what real carbon data verification means, because a lot of what passes for it falls short.
Verification is not a self-reported spreadsheet with a logo on it. It is not a PDF from a supplier with a number and no methodology.
Real verification involves:
- Third-party review of actual data: energy inputs, process emissions, allocation methods — examined by someone independent
- Traceability from raw measurement to final number: every step in the calculation visible and auditable
- A timestamp: when was this number calculated, and from what data? Carbon numbers without dates are carbon guesses.
The question is not whether your carbon data is good enough. The question is whether anyone can prove it.
The financial cost of this trust gap? That’s next.